For many years it has been common practice to join pipe sections together by providing the sections with an annular flange at each end and bolting the sections together by means of such flanges. Many pipelines so constructed are intended to carry high-pressure steam or corrosive or toxic chemicals under pressure. Experience has shown that on occasion high-pressure flange leaks occur in such pipe lines, resulting in injury to personnel and damage to equipment.
Various types of safety shields have been designed for the purpose of preventing personal injury and damage to equipment caused by such flange leak. Generally they have comprised a strip of metal or a fabric impregnated with a polymer, the strip having a flange, which in the case of metal is generally segmented, along each longitudinal edge. The shields are wrapped about the pipe flanges with the opposing ends overlapping. Some shields are secured in place by means of screws which hold the overlapping ends together. Others are secured by means of draw strings.
For the most part, such shields have been opaque, so that the presence of a flange leak is not observed until the fluid seeps out of the shield and drips to the floor or other surface below. Depending upon the material from which the shield is composed, it may be destroyed by leakage of corrosive liquids.
More recently (see U.S. Pat. No. 4,216,980), there has been devised a safety shield comprising an elongated, flexible strip of polytetrafluoroethylene having longitudinal edge of flange portions which are segmented and overlap when the shield is wrapped around a pipe flange. A lace is passed through each of the several segments and tied in order to secure the shield to the pipe flange. Such shield has a number of disadvantages. It is difficult and expensive to fabricate, and its application to a pipe flange is tedious and time-consuming. Also, the removal and reapplication thereof in order to repair a leak is a slow and costly operation.
A primary object of this invention is to provide a novel safety shield for pipe coupling flanges which is of simple construction and may be applied to and removed from a pipe coupling flange by means of a simple snap on-snap off procedure.
Another object of this invention is to provide a novel method for making a safety shield for a pipe flange which is inexpensive and relatively easy to carry out.
Still another object of this invention is to provide a safety shield which is transparent, thereby enabling workers to observe leaks at pipe flanges before the fluid, which may be corrosive, runs onto the surface below the flange.
Yet another object of this invention is the provision of a safety shield of corrosion-resistant material which can be removed and replaced many times during its useful life.
A still further object of this invention is a novel safety shield which, after installation, can be heat shrunk in place to obtain a tight fit about the pipe flange.
These and other objects of this invention will become further apparent from the accompanying drawings and description of preferred embodiments.